Delete the symbol a from legend

Question

I need to delete that symbol 'a' that is coming in the legend, plus I would like to know if there is a possibility to place the label on the top of the bars.

This my example file:

Residue,Position,Weight,SVM Count,Odd,Ttest,lower,upper,Resistance
G163R,163,0.357,49,19.9453848,6.978518E-82,5.6628402,70.2925768,Accessory
V165I,165,0.268,49,2.98167788,1.60934E-80,1.25797484,7.06728692,Novel
N155H,155,0.253,50,38.6089584,1.089188E-83,9.5815554,155.7070612,Major

library(ggplot2)
m <- read.csv('example.csv', header=T, row.names=1)
boxOdds = m$Odd

df <- data.frame(
    yAxis = length(boxOdds):1,
    boxnucleotide = m$Position,
    boxCILow = m$lower,
    boxCIHigh = m$upper,
    Mutation = m$Resistance)
ticksy<-c(seq(0,0.3,by=.1), seq(0, 1, by =.5), seq(0, 20, by =5), seq(0, 150, by =50))
ticksx<-c(seq(0,300,by=25))
p <- ggplot(df, aes(x = boxnucleotide, y = boxOdds, colour=Mutation,label=rownames(m)))
p1 <- p + geom_errorbar(aes(ymax = boxCIHigh, ymin = boxCILow), size = .5, height = .01) +
    geom_point(size = 1) +
    theme_bw() +
    theme(panel.grid.minor = element_blank()) +
    scale_y_continuous(breaks=ticksy, labels = ticksy) +
    scale_x_continuous(breaks=ticksx, labels = ticksx) +
    coord_trans(y = "log10") +
    ylab("Odds ratio (log scale)") +
    scale_color_manual(values=c("#00BFC4","#F8766D","#619CFF")) +
    xlab("Integrase nucleotide position") + 
    geom_text(size=4,hjust=0, vjust=0)+
    theme(legend.position = c(0.9, 0.9))
p1

I already tried all possible solutions from Remove 'a' from legend when using aesthetics and geom_text but none worked out